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2002 G500. 182K miles. 1 Owner who never used the differential locks. Dealer serviced.
So today I went to a dirt lot and decided to test out the differential locks. I pressed the center diff lock button and the yellow light came on. I could hear the vacuum pump running. It ran and ran for a few minutes and the RED indicator light never came on. I drove the car slowly in the dirty turning side to side. Still nothing. The yellow light stayed on and the pump stayed on. I got back home and turned the car off with the center lock button pressed (yellow light on) and opened the hood. Pump was pretty loud. I made sure the connections at the pump and valve switches were tight and nothing had come off. I went under the car and checked the vacuum hose that connected to the top of the TC and it was attached.
I don't know if the aux vacuum pump is or is not making enough vacuum to engage the center diff or there is a leak somewhere. I tried to follow the line from the valve switch output to the TC and it seemed fine. I need to take the driver side inner wheel well out and see if the connections to the reservoir are good.
Anyways the pump kept running indefinitely even after I shut off the car with the center diff lock requested. I have a feeling maybe the pump is bad? How should I begin testing this? I will be flushing out the TC and differentials this weekend with Redline MT90 and 75w90 fluid.
Any guidance is appreciated!!!!! I want to know if the pump should turn off after reaching a certain vacuum level? I was thinking of picking up a vacuum gauge and seeing how much the pump is putting out.
I think that you are starting in the right place. A G with the history yours has is likely to need the diff flushed. I'm no mechanic but I see this advice over and over. People often regain full function of this after a flush.
I think that you are starting in the right place. A G with the history yours has is likely to need the diff flushed. I'm no mechanic but I see this advice over and over. People often regain full function of this after a flush.
I agree with the diff fluids need to be changed and the diff lock fluid flushed; but neither has anything to do with the center diff lock on the TC as it is strictly vacuum operated. The diff lock vacuum diaphragm in the TC has been known to fail, and that would be the cause of the OP's problem. Also, check the small vacuum hoses around the diff lock valves in the firewall for breakage or disconnects.
The TC oil also needs to be changed. Just be sure that you use the right oil.
I agree with the diff fluids need to be changed and the diff lock fluid flushed; but neither has anything to do with the center diff lock on the TC as it is strictly vacuum operated. The diff lock vacuum diaphragm in the TC has been known to fail, and that would be the cause of the OP's problem. Also, check the small vacuum hoses around the diff lock valves in the firewall for breakage or disconnects.
The TC oil also needs to be changed. Just be sure that you use the right oil.
Thank you both. I will try after changing both fluids and having a shop flush the hydraulic brake fluid. I know the center lock is purely vacuum operated so it has to be the diaphram (http://fourbyfourclub.com/W463Transm...eDiaphragm.htm) or a problem with the pump/line.
Can anyone guide me as to how to test the lines for a leak or test if the vacuum is creating enough pressure? I really do not want to pay 100$+ an hour for diag!
So did those diagrams help you? A little followup is always nice.
hey! Sorry got a little busy with things. So this weekend I was updating the front bumper and headlight covers.
I wanted ted to check the vacuum line going to the vacuum reservoir tank and guess what I found??
The plastic elbow connector for the line that goes from the pump to the reservoir tank behind the driver side wheel well was rotted and broke. The vacuum line was completely off. So I’m assuming no vaccum was being made and therefore my center lock isn’t engaging.
The elbow is 1.5$ at my dealer but they only have them in Germany right now so I’m looking elsewhere. Part number is 002-990-68-71
. If anyone else is having diff problems, definitely check all vaccum lines. I’m sure the Arizona heat has done damage to many plastic pieces.
I pulled the wheel well cover. I have the exact part broken. Thanks again for saving me from a headache. Ordered part 002-990-68-71. “...special order... $4.50...”.
I looked in autozone and they have assorted packs but no 90 degree elbow. I also went to Another parts store... nothing. Went to Home Depot... couldn’t find it.
resurrecting this one since it is the best in here about vacuum on the diff lock system.
If i turn the ignition to on, but not start the engine, the pump keeps running and won't engage the locker. Engine on, it engages in a few seconds. The rear and front locker can be a bit slow sometimes but in general engage. There are no obvious failures or vacuum leaks on the front half of the system. I am leaning towards the transfer case diaphragm failing; any thoughts? Fluid and system were cleaned and changed less than two years ago.
resurrecting this one since it is the best in here about vacuum on the diff lock system.
If i turn the ignition to on, but not start the engine, the pump keeps running and won't engage the locker. Engine on, it engages in a few seconds. The rear and front locker can be a bit slow sometimes but in general engage. There are no obvious failures or vacuum leaks on the front half of the system. I am leaning towards the transfer case diaphragm failing; any thoughts? Fluid and system were cleaned and changed less than two years ago.
Hi, did you fix the problem? It seems similiar to mine probl
01-17-2018, 11:05 PM
2002 G500 Differential Lock Issue :(
